In general, switches are utilized to switch devices from an open/off position to a closed/on position in order to control the operation of particular devices and/or systems. Normally, mechanical switches are actuated to control an operation, especially in hydraulic devices such as, for example, automotive systems. Mechanical switches can be furnished in different sizes. Such switches are typically, however, not very compact and are very expensive and often require additional hardware for mounting.
A pressure switch is a type of switch in which the switching action can be triggered by a pressure in the surrounding environment. In some situations, pressure switches may be connected between the primary and secondary hydraulic circuits or between one of the hydraulic circuits and a booster circuit. Such pressure switches provide a reliable indication of pressure while simultaneously obviating switch actuation caused by excess pressures. In one prior art implementation, the pressure switch can be operatively engaged by a differential piston to actuate in response to movement thereof. The differential piston includes two piston elements telescopically engaged one within the other and maintained in an extended relationship by means of a preload spring. The piston elements are collapsible one within the other when the pressure is above a predetermined minimum pressure, which damages the entire pressure switch.
Another conventional pressure switch includes the use of a push member, two contact points, a spring member and a rectangular box, which receives all the parts therein. Such a pressure switch may improve the switching operation for hydraulic devices, for example, but increases the manufacturing cost. Similarly, the majority of prior art pressure switches can typically be configured with a diaphragm to be impinged upon by a pressure media such as air or gas under pressure. The diaphragm may actuate the switch contacts of the pressure switch upon reaching a predetermined pressure. These pressure switches, however, tend to operate only at relatively low pressure levels, and are not sufficiently miniaturized, since they frequently occupy more space. Additionally, such pressure switches are affected by surrounding dust, which tends to damage the diaphragm, which is not properly sealed.
A need therefore exists for a low cost, self-cleaning pressure switch, which can be mounted in line to an existing device or components such as a hydraulic circuit without any additional hardware. It is believed that such an improved pressures switch would find particular usefulness in automotive systems, such as, for example, anti-lock braking systems, sports utility vehicles, snowmobiles, all terrain vehicles (ATV's) and so forth.